Where in the US is the Omicron variant and how quickly is it spreading?

New strain has been found in at least 45 states

It’s been only a month since South Africa first reported the discovery of the Omicron variant of coronavirus to the World Health Organisation (WHO) but the new strain has already had a huge impact around the world.

The latest form of the disease, which is still being studied by scientists, has prompted travel bans, calls for renewed mask mandates and efforts from public health authorities in more than 89 countries where it has been detected to try and stop the variant from spreading further.

The first US case of Omicron was announced on 1 December, from an individual who had travelled from South Africa to San Francisco in late November. The traveller had received the coronavirus vaccine but not a booster shot.

“We knew that it would be just a matter of time before the first case of Omicron would be detected in the US,” White House chief medical and Covid adviser Dr Anthony Fauci said at the time, adding. “We know what we need to do to protect people. Get vaccinated, if you’re not already vaccinated. Get boosted.”

Since then, officials across the country have announced new cases of Omicron in their state.

Here’s what we know about the variant’s spread in the US.

Where in the US is Omicron?

The variant has been found in at least 45 states and it now makes up 73 per cent of reported cases across the US, up from just 3 per cent a week earlier, according to the Centres for Disease Control (CDC).

A full map of which states have detected the strain can be found on the CDC’s website.

In some states, like New York and New Jersey, Omicron may now account for as much as 92 per cent of cases, according to the CDC, while that number is thought to be as high as 96 per cent in Washington State.

New York City recently raised alarms when public health officials noted that the Covid positivity rate in the city had doubled in one week, from 3.82 per cent on 10 December to 7.68 per cent on 17 December.

“We have seen a very substantial increase in cases in the last few days,” New York mayor Bill de Blasio said during a press briefing last week.

“It is clear that the Omicron variant is here in New York City in full force.”

New York’s Cornell University recently closed early for the holidays and shifted to virtual classes, after 903 students tested positive for coronavirus, some of them who were fully vaccinated and still got the Omicron variant.

“Omicron is spreading at a rate we have not seen with any previous variant,” WHO director-general Tedros Adhanom Ghebreyesus said this week during a Covid briefing.

In South Africa, one of the countries that first identified the variant, Omicron has spread twice as fast as the Delta variant, overtaking it as both the fastest spreading and most dominant version of the virus in the country.

What do we know about how the Omicron variant works and how to treat it?

Because the variant was only discovered weeks ago, scientists are still in the early stages of studying Omicron, though initial studies and analyses offer some clues as to how it compares to other forms of the first.

Early studies out of South Africa showed patients getting seemingly less severe cases of coronavirus than in previous waves, with 29 per cent fewer being admitted to the hospital.

Still, experts caution that these results could reflect the country’s vaccination efforts and the high level of citizens who were previously infected with coronavirus.

In the US, only one person has died so far from Omicron - reportedly an unvaccinated man from Texas - but this could be a reflection that young, well-vaccinated people were the ones testing positive so had healthier responses to the new form of the virus.

Initial data out of the US and other countries points to another trend: Omicron could be better at evading the protections offered by vaccines or antibodies from previous infections.

Among the 43 initial Omicron cases in the US analysed by the CDC, 14 people had had additional doses of the vaccine,and six were previously down with coronavirus. A majority of South Africans have already had the coronavirus once and yet now the new variant is spreading in large numbers within the country.

Additionally, Omicron appears to spread more quickly than other forms of coronavirus. A British study found that the strain was more than three times more likely to spread inside a household than the Delta variant.

As to treating Omicron, public health officials say approved coronavirus vaccines, with the vital addition of a booster shot, are still an effective way to prevent serious illness.

“Our booster vaccine regimen work against Omicron,” Dr Fauci said this week. “And so the message remains clear: If you are unvaccinated, get vaccinated. And particularly in the arena of Omicron, if you are fully vaccinated, get your booster shot.”

An analysis from South Africa’s largest health care administrator found that two shots of the Pfizer vaccine were 70 per cent effective at keeping people out of the hospital, influential but still less effective than against the Delta variant, where vaccines offered 90 per cent protection from hospitalisation.

How much protection one receives may depend on what vaccine they have.

British researchers found that those who were six months out from receiving two doses of the AstraZeneca vaccine had no protection against Omicron. Two doses of the Pfizer vaccine provided 34 per cent effectiveness, while a booster more than doubled that figure.

What does the future of the Omicron variant look like in the US?

If current initial trends hold and Omicron is both milder and faster-spreading than other forms of the coronavirus, the variant could still wreak havoc in already weary health systems across the country.

“You may only have one per cent of people infected hospitalised versus 10 per cent from Delta, but if you have a million more people infected because it’s spread so much more quickly, that means you’ll have overflowing hospitals at this rate,” New York governor Kathy Hochul said last week.

Meanwhile, the original Covid crisis in US hospitals never ended.

More than 1,000 Americans are dying from coronavirus every day, with more fatalities this year compare to 2020. Hospitalisations from Covid are rising in 42 states.

“The level of care that we’ve come to expect in our hospitals no longer exists,” virologist John Lowe told The Atlantic.

Andy Slavitt, former senior adviser to the White House Covid team, has said Omicron infections in the US seem to be doubling every few days, and could overtake the Delta variant in the US, peaking by the third week of January.